Inherited intellectual disability can be reversed

Published in The Hindu on April 12, 2012

Studies undertaken in adult mice showed that the Fragile X syndrome (FXS) that causes the most common forms of inherited intellectual disability, including autism, can be reversed.  Fragile X syndrome is caused by “mutations in the fragile X mental retardation 1 (FMR1) gene.”

A paper published today (April 12) in the journal Neuron , showed that such reversals can be achieved through chronic pharmacological intervention (mGlu5 inhibition) to correct for altered glutamate signalling.  The study was undertaken in mice. The good news is that such reversals can be achieved even when the mice have become adults and where FXS has already become well established. Previous studies have shown the usefulness of pharmacological mGlu5 inhibition.

The scientists started treatment in adult mice (4-5 weeks old) that have a fully developed brain that is still “highly plastic.” The chronic treatment lasted for four weeks. The treated mice showed reversal of “learning and memory deficits, hyperreactivity to sensory stimuli.  Chronic treatment for 17 weeks reversed elevated locomotor activity.

“The important and therapeutically relevant conclusion is that a broad spectrum of FXS phenotypes — biochemical, structural, and behavioural — can be improved with treatment onset in early adulthood in mammals,” they write. Unlike earlier studies, the present study shows that disability caused by Fragile X syndrome can be reversed by resorting to chronic treatment “starting in young adulthood.”